1. Field of the Invention
The present invention relates to a vehicle-applied display unit to visualize an display image of a luminous display source as a virtual image on a combiner standing on a dashboard.
2. Description of the Related Art
In a vehicle-applied display unit to visualize, or to have a driver recognize, a virtual image of a display image including supporting information about travelling by means of reflection for leading an image light of the display image of a luminous display source accommodated in a dashboard to an eye point of a driver, an opening for leading the image light of the display image of the luminous display source to a front windshield or a combiner which reflects the image light is usually formed on a top face of the dashboard.
An outer light entering a vehicle-inside from an vehicle-outside further enters the opening and is irradiated to the luminous display source. Therefore, measures for preventing a washout (i.e., weakening of contrast) of the virtual image of the display image are necessary.
For example, Japanese Utility Model Application Laid-open No. 4-85370 discloses a prior art vehicle-applied display unit with one measure, wherein two polarizing plates having respective polarization directions different by 90 degrees each other are placed on an inner surface portion of a front windshield to which the image light of the display image passing the opening of the dashboard is irradiated. The two polarizing plates intercept the outer light irradiated to the luminous display source.
With respect to the above prior art disclosed in Japanese Utility Model Application Laid-open No. 4-85370, however, since because the outer light enters a vehicle with various angles from various portions such as the front windshield and door windshields, the outer light entering the vehicle-inside from the portions without the polarizing plate cannot be prevented from reaching the luminous display source.
An object of the present invention is to provide a vehicle-applied display unit, wherein the contrast of a virtual image, visible from an eye point, of a display image of a luminous display source is prevented from lowering by the influence of the outer light entering the vehicle-inside from the vehicle-outside or the lowering of the contrast is reduced so as to keep the visibility of the virtual image of the display image of the luminous display source well.
In order to achieve the above object, as a first aspect of the present invention, a vehicle-applied display unit comprises: a dashboard of a vehicle positioned ahead of an eye point in the vehicle; a luminous display source provided inside the dashboard; an opening provided on the dashboard; and a combiner standing on the dashboard visibly from the eye point and reflecting image light, toward the eye point, of a display image emitted from the luminous display source and passed the opening, wherein the combiner is arranged on an optical path of a portion, of outer light entering a vehicle-inside from a vehicle-outside, going toward the luminous display source through the opening at least over a whole extent, in a vehicle-width direction, of the portion of the outer light for at least partially enclosing the opening over a front through both sides portions thereof and is made of light-attenuation processed material capable of at least attenuating the portion of the outer light.
As a second aspect of the present invention, based on the first aspect, the combiner is arcuately formed in a vehicle-width direction with an inside surface of the combiner facing the eye point in such a manner that both longitudinal ends of at least a portion, of the combiner, on which the image light of the display image is irradiated are positioned rearward of a central portion thereof and also in such a manner that, in a vehicle-height direction, the portion of the combiner has a straight cross-section while inclinedly standing rearward with a top thereof being positioned rearward of a bottom thereof.
As a third aspect of the present invention, based on the first aspect, a measuring instrument displaying a state of the vehicle is arranged on a portion, of the dashboard, located nearer the eye point than the opening is, and the combiner has such an external form that a contour of the combiner visible from the eye point almost encloses a virtual image of the display image and a real image of the measuring instrument, the virtual image being obtained by irradiation of the image light of the display image and being visible from the eye point.
As a fourth aspect of the present invention, based on the third aspect, the measuring instrument includes a plurality of meter units with intervals in the vehicle-width direction and the combiner is arranged in a manner that a portion of the combiner reflects the image light of the display image of the luminous display source toward the eye point, the portion being positioned between two meter units adjacent to each other.
As a fifth aspect of the present invention, based on the first aspect, a recess is formed on a top face of the dashboard, and the combiner stands inside the recess while partially enclosing the opening formed in the recess so that the combiner is positioned outside a vehicle forward sight from the eye point.
As a sixth aspect of the present invention, based on the first aspect, a steering wheel is arranged between the dashboard and the eye point, and the combiner has a regular-arcuated top edge, a curvature of the top edge being different from that of the steering wheel according to a back-and-forth position difference therebetween from the eye point.
As a seventh aspect of the present invention, based on the first aspect, an optical path changing member to make the optical path of some area, in a vehicle-height direction, of the portion of the outer light go away from the luminous display source is arranged between the luminous display source and the combiner, and the combiner is arranged on the optical path of at least a remaining area of the portion of the outer light.
As an eighth aspect of the present invention, based on any one of the first to seventh aspects, a polarizing plate is put on one surface of the combiner for attaining light attenuation, and a second polarizing plate having a polarization direction different from that of the polarizing plate by 90 degrees is arranged between the opening and the luminous display sources.
As a ninth aspect of the present invention, based on the eighth aspect, the luminous display source has a third polarizing plate having a same polarization direction as that of the second polarizing plate on an emitting surface of the image light of the display image.
As a tenth aspect of the present invention, a vehicle-applied display unit comprises: a dashboard of a vehicle positioned ahead of an eye point in the vehicle; a luminous display source provided inside the dashboard; an opening provided on the dashboard; and a combiner standing on the dashboard visibly from the eye point and reflecting image light, toward the eye point, of a display image emitted from the luminous display source and passed the opening, wherein a recess is formed on a top face of the dashboard, and the combiner stands inside the recess and ahead of the opening formed in the recess so that the combiner is positioned outside a vehicle forward sight from the eye point.
As an eleventh aspect of the present invention, based on the tenth aspect, a measuring instrument displaying a state of the vehicle is arranged on a portion, of the dashboard, located nearer the eye point than the opening is, and the combiner has such an external form that a contour of the combiner visible from the eye point almost encloses a virtual image of the display image and a real image of the measuring instrument, the virtual image being obtained by irradiation of the image light of the display image and being visible from the eye point.
As a twelfth aspect of the present invention, based on the eleventh aspect, the measuring instrument includes a plurality of meter units with intervals in the vehicle-width direction and the combiner is arranged in a manner that a portion of the combiner reflects the image light of the display image of the luminous display source toward the eye point, the portion being positioned between two meter units adjacent to each other.
As a thirteenth aspect of the present invention, based on any one of the tenth to twelfth aspects, a steering wheel is arranged between the dashboard and the eye point, and the combiner has a regular-arcuated top edge, a curvature of the top edge being different from that of the steering wheel according to a back-and-forth position difference therebetween from the eye point.
According to the first aspect of the present invention, the opening to make the image light of the display image of the luminous display source in the dashboard pass therethrough is provided, and the combiner being a light-attenuation treated member partially encloses the opening over the front through both sides portions thereof. Therefore, a portion, going toward the luminous display source, of the outer light entering the vehicle-inside from the vehicle-outside is attenuated at least over the whole extent in the vehicle-width direction.
According to the second aspect of the present invention, because the combiner partially enclosing the opening over the front through both sides portions thereof has the straight section in the vehicle-height direction, the virtual image of the display image on the combiner visible from the eye point is not distorted in the vehicle-height direction.
According to the third aspect of the present invention, because the combiner has such an external form that a contour of the combiner visible from the eye point almost encloses a virtual image of the display image and a real image of the measuring instrument, which virtual image is obtained by irradiation of the image light of the display image and being visible from the eye point, the virtual image of the display image and the real image of the measuring instrument are visible as one combination display of a single measuring instrument unit from the eye point.
According to the fourth aspect of the present invention, because the combiner is arranged in a manner that a portion of the combiner reflects the image light of the display image of the luminous display source toward the eye point, which portion is positioned between two meter units adjacent to each other, the virtual image of the display image on the combiner visible from the eye point and the real image of the measuring instrument are arranged in the vehicle-width direction.
According to the fifth aspect of the present invention, because the opening on the dashboard is formed inside the recess formed on the top face of the dashboard and the combiner visible from the eye point stands inside the recess while partially enclosing the opening, the combiner can be positioned outside the vehicle forward sight from the eye point by adjusting the height of the combiner and the depth of the recess.
According to the sixth aspect of the present invention, the contour of the combiner is hidden by the steering wheel invisibly from the eye point.
According to the seventh aspect of the present invention, the optical path changing member to make the optical path of some area, in a vehicle-height direction, of the portion of the outer light go away from the luminous display source is arranged between the luminous display source and the combiner and the combiner is arranged on the optical path of at least a remaining area of the portion of the outer light, the whole portion of the outer light passing the opening of the dashboard toward the luminous display source can be attenuated.
According to the eighth aspect of the present invention, the outer light component having passed the polarizing plate put on the one surface of the combiner is intercepted by the second polarizing plate on the way to the luminous display source from the opening on the dashboard.
According to the ninth aspect of the present invention, the image light of the display image polarized by the third polarizing plate provided on the luminous display source can pass the second polarizing plate having the same polarization direction as that of the third polarizing plate and arranged on the way to the opening from the luminous display source. The image light of the display image polarized by the third polarizing plate, however, cannot pass the polarizing plate having a different polarization direction as that of the third or second polarizing plate by 90 degrees and therefore is reflected toward the eye point.
According to the tenth aspect of the present invention, the opening to pass the image light of the display image emitted from the luminous display source in the dashboard toward the combiner is formed in the recess formed on the top face of the dashboard. And, because the combiner visible from the eye point stands inside the recess and ahead of the opening, some inner surface of the recess is positioned behind the combiner when viewed from the eye point, whereby the sight through the combiner from the eye point is the inner surface of the recess even if the combiner is formed of a transparent member.
According to the eleventh aspect of the present invention, because the combiner has such an external form that a contour of the combiner visible from the eye point almost encloses a virtual image of the display image and a real image of the measuring instrument, which virtual image is obtained by irradiation of the image light of the display image and being visible from the eye point, the virtual image of the display image and the real image of the measuring instrument are visible as one combination display of a single measuring instrument unit from the eye point.
According to the twelfth aspect of the present invention, because the combiner is arranged in a manner that a portion of the combiner reflects the image light of the display image of the luminous display source toward the eye point, which portion is positioned between two meter units adjacent to each other, the virtual image of the display image on the combiner visible from the eye point and the real image of the measuring instrument are arranged in the vehicle-width direction.
According to the thirteenth aspect of the present invention, the contour of the combiner is hidden by the steering wheel invisibly from the eye point.
According to the above-described structures of the present invention, the following advantages are provided.
(1) The portion of the outer light entering the vehicle-inside from the vehicle-outside passing the opening of the dashboard toward the luminous display source is attenuated at least over the whole extent in the vehicle-width direction by passing the combiner so that the lowering of the contrast of the virtual image, of the display image of the luminous display source, visible from the eye point can be reduced or prevented. Thereby the visibility of the virtual image of the display image of the luminous display source can be better.
(2) The combiner is arranged to partially enclose the opening making the image light of the display image of the luminous display source in the dashboard pass therethrough, while not distorting the virtual image of the display image on the combiner in the vehicle-height direction, which virtual image is visible from the eye point by means of the irradiation of the image light of the display image from the luminous display source. Like this, the combiner can easily prevent the virtual image of the display image on the combiner from being distorted in the vehicle-height direction.
(3) The virtual image of the display image of the luminous display source and the real image of the measuring instrument are visible as one combination display of a single measuring instrument unit from the eye point by means of the contour of the combiner. Like this, the combiner can attain the visual unification of the virtual image of the display image of the luminous display source and the real image of the measuring instrument, while reducing the sense of visual incongruity.
(4) The virtual image of the display image on the combiner and the real image of the measuring instrument are arranged in the vehicle-width direction outside the forward sight of the vehicle from the eye point. Therefore, the forward sight of the vehicle especially in the vehicle-height direction can be wider than that of a case that the area of the virtual image is arranged over or under the measuring instrument.
(5) The combiner has a height according to the depth of the recess so that the combiner can be outside the forward sight of the vehicle from the eye point. Therefore, even if the combiner is formed of a translucent or a non-transparent member, the combiner does not narrow down the forward sight.
(6) The contour (i.e., the top edge portion) of the combiner is hidden by the steering wheel so that the portion is invisible from the eye point, thereby reducing the visual sense of incongruity.
(7) The whole outer light passing through the opening of the dashboard toward the luminous display source is attenuated by means of the combined actions of the combiner and the optical path changing member so that the lowering of the contrast of the virtual image, visible from the eye point, of the display image of the luminous display source can be reduced or prevented by the influence of the outer light entering the vehicle-inside from the vehicle-outside toward the luminous display source, thereby further improving the visibility of the virtual image of the display image of the luminous display source.
(8) The outer light component having passed the polarizing plate put on the one surface of the combiner is intercepted by the second polarizing plate on the way to the luminous display source from the opening on the dashboard so that the lowering of the contrast of the virtual image, visible from the eye point, of the display image of the luminous display source can be reduced or prevented by the influence of the outer light entering the vehicle-inside from the vehicle-outside toward the luminous display source, thereby further improving the visibility of the virtual image of the display image of the luminous display source.
(9) The image light of the display image reached the combiner from the luminous display source through the opening on the dashboard does not reach the front windshield so that the virtual image of the display image on the combiner is not disturbed by the virtual image (i.e., ghost image) of the display image on the front windshield, thereby further improving the visibility of the virtual image of the display image of the luminous display source.
(10) Even if the combiner is transparent, the sight from the eye point is obstructed by the inner surface of the recess so that the virtual image of the display image on the combiner is visible from the eye point with a contrast difference from the inner surfaces of the recess, whereby the lowering of the contrast of the virtual image of the display image visible on the combiner caused by the outer light entering the vehicle-inside from the vehicle-outside is prevented, thereby obtaining good visibility of the virtual image of the display image on the combiner.
(11) The virtual image of the display image of the luminous display source and the real image of the measuring instrument are visible as one combination display of a single measuring instrument unit from the eye point by means of the contour of the combiner. Thus, the combiner can attain the visual unification of the virtual image of the display image of the luminous display source and the real image of the measuring instrument, while reducing the sense of visual incongruity.
(12) The virtual image of the display image on the combiner and the real image of the measuring instrument are arranged in the vehicle-width direction outside the forward sight of the vehicle from the eye point. Therefore, the forward sight of the vehicle especially in the vehicle-height direction can be wider than that of a case that the area of the virtual image is arranged over or under the measuring instrument.
(13) The contour (i.e. the top edge portion) of the combiner is hidden by the steering wheel so that the portion is invisible from the eye point, thereby reducing the visual sense of incongruity.